kWh Calculator

Calculate electrical energy consumption in kilowatt-hours.

Use 1 for a single day. For a monthly or annual estimate, enter the number of days.

Energy formula

Energy (kWh) = Power (kW) × Time (hours).

kWh Formula

A kilowatt-hour measures electrical energy consumed over time. Convert power to kilowatts, then multiply by the number of hours used.

kWh = kW × Hours

For watts: kWh = Watts × Hours ÷ 1,000

How to Use the kWh Calculator

1

Enter Power

Enter the appliance or electrical load in watts or kilowatts.

2

Enter Usage Time

Enter how long the load operates and choose hours, minutes or days.

3

Set the Period

Choose the usage frequency and number of usage days when estimating recurring consumption.

4

Calculate

Review daily, monthly and annual energy consumption estimates.

Example

A 1,000 W appliance running for 5 hours.

1,000 W = 1 kW.

Energy = 1 kW × 5 hours = 5 kWh.

Consumption = 5.00 kWh

Frequently Asked Questions

A kilowatt-hour is a unit of electrical energy. It represents using 1 kilowatt of power continuously for 1 hour.
Multiply the wattage by the operating time in hours and divide by 1,000. For example, 500 W used for 4 hours consumes 2 kWh.
No. kW measures power, while kWh measures energy consumed over time.
This calculator focuses on energy consumption in kWh. Electricity cost requires a separate energy-price or electricity-bill calculation using your applicable tariff.

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